Ectopic beat (or cardiac ectopy) is a disturbance of the cardiac rhythm frequently related to the electrical conduction system of the heart, in which beats arise from fiber or group of fibers outside the region in the heart muscle ordinarily responsible for impulse formation (i.e., the sinoatrial node). Depending upon the origins of the ectopic beat within the myocardium, an ectopic beat can be further classified as either:

Some patients describe this experience as a 'flip' or a 'jolt' in the chest, while others report dropped or missed beats. Such extrasystoles are more common during periods of stress or debility; they may also be triggered by consumption of some food like alcohol, strong cheese, or chocolate.